So if Michelin gets its way, there won't be quite as many once they adapt their tire-wheel combination, dubbed the Tweel, to the automotive and bicycle markets.
The Tweel consists of a cable-reinforced band of conventional "tire" rubber with molded tread, a shear band just below the tread that creates a compliant contact patch, and a series of energy-absorbing spokes. The rectangular, polyurethane spokes can be designed to have a range of stiffnesses, so engineers can control how the Tweel handles loads. The inner hub contains a matrix of deformable plastic structures that flex under load and returns to its original shape.
Currently, the Tweel is being used for low-speed, low-weight applications, such as an iBot wheel chair for Independence Technology and a skid loader. It might be seen on cars in a decade or so. Tests on production cars have shown it is within 5% of a conventional tire and wheel's rolling resistance.